Various embodiments of a blast mitigation and ballistic protection system are described herein. In particular, the embodiments described herein relate to an improved system for blast mitigation and ballistic protection system and improved components for such systems.
Protective armor typically is designed for several applications types: personal protection such as helmets and vests, vehicle protection such as for high mobility multi-wheeled vehicles (HMMWVs), and rigid structures such as buildings. Important design objectives for personal protection include, for example, protection against ballistic projectiles, low weight, and good flexure. Vehicles and rigid structures often require superior ballistic and blast protection and low cost per unit area.
Blast protection typically requires the material to have the structural integrity to withstand the high loads of blast pressure. Ballistic protection typically requires the material to stop the progress of bomb fragments ranging in size from less than one millimeter to 10 mm or more and traveling at velocities in excess of 2000 meters per second for smaller fragments.
Accordingly, personal protective armor is often made of low weight, high tech materials having a high cost per unit area. High unit area cost may be acceptable to the user because people present low surface area relative to vehicles and buildings. The materials used in personal protective armor products do not need high load bearing capabilities because either the body supports the material, such as in a vest, or the unsupported area is very small, such as in a helmet.
As a result of the blast, ballistic, and low unit area cost requirements for vehicles and structures, the materials used in blast protection are typically heavier materials, including for example, metals and ceramics. Such materials may not always be low cost. Such materials may further be of usually high weight per unit area.
It is also desirable to improve the energy absorption capacity of wood and wood composites components, subassemblies, and structures. A common wood frame construction method uses wood or steel studs, and wood or steel framing with plywood, Oriented Strand Board (OSB) sheathing panels, or stucco sheathing. The framing/sheathing combination forms shear walls and horizontal diaphragms which resist horizontal and vertical loads applied to the structure. This form of construction is used in the majority of single family homes in the United States, as well as a significant portion of multi-family, commercial, and industrial facilities. The resistance of conventional light-frame wood buildings to extreme events such as air blast from explosive weapons or hurricane winds depends in large part on the energy absorbing characteristics of the framing members and connections therebetween. It is desirable to improve the energy absorbing characteristics of wood structures.
International Organization for Standardization (ISO) containers are commonly used to house soldiers, disaster relief workers, contractors, and others where temporary and rapidly deployable shelters are used. Additionally, containers are used for mobile medical units, control and command centers, communications, equipment storage, and the like. Many of these applications are located in areas exposed to threats such as car bombs, mortars, improvised explosive devices (IEDs), small arms fire, etc. Containers converted for these applications typically do not have systems for blast and fragmentation mitigation.
Field housing for the military is vulnerable to forces encountered during the blast wave of bomb explosions. The forces generated during explosions are capable of fracturing and dislodging framing components. The resulting airborne debris presents a danger to troops within the confines of a building as well as to troops in adjacent buildings and surrounding areas. Therefore, a connector is required to minimize the lethal force of dislodged framing material.